Solid state input device

ABSTRACT

Input devices having a thin profile and good comfort and feel are disclosed. In embodiments, an input device includes a sensor layer configured to effectuate a key press upon application of an activation force, and a collapsible layer coupled to the sensor layer. The collapsible layer may be configured to collapse in response to a collapsing force that is substantially equal to the activation force. When the collapsible layer collapses, the sensor layer may simultaneously effectuate the key press in response to application of the collapsing force.

BACKGROUND

Input devices for modern computer systems are typically used to convertanalog inputs (e.g., touches, clicks, motions, gestures, button presses,etc.) into digital signals for computer processing. An input device caninclude any device used to provide data and control signals to aninformation processing system such as a computer. Some non-limitingexamples of input devices include keyboards, key pads, computer mice,remote controls, gaming controllers, joysticks, trackballs, and thelike.

Input devices, such as keyboards, are typically designed to maximizecomfort and feel when being used. A typical keyboard that is comfortableto use and has good feel is one that has keys that provide resistancewhen pressed until a certain point at which the keys compress toeffectuate a key press. This force profile may be referred to as anS-curve force profile. Conventional keyboard designs that successfullyachieve this force profile include mechanical keys such as scissor keys.However, keyboards that utilize mechanical keys are often bulky, heavy,and occupy a lot of space, which are not desirable for keyboards thatare designed to be smaller and more compact. To decrease keyboard sizeand weight, such keyboards may sacrifice comfort and feel, therebylosing customer appeal. Improvements to such keyboards are desired.

SUMMARY

Embodiments are directed to keyboard that has good comfort and feel butis also flexible and compact in size. In certain embodiments, thekeyboard is a solid state keyboard that includes a collapsible layercoupled to a sensor layer. The collapsible layer may have a forceprofile that is substantially similar to an S-curve force profile. Thecollapsible layer and sensor layer may be designed with one another inmind such that when the collapsible layer collapses upon application offorce from a user, the sensor layer effectuates a key press in aseamless manner.

Certain embodiments of the invention include an input device including asensor layer configured to effectuate a key press upon application of anactivation force, and a collapsible layer coupled to the sensor layer.The collapsible layer may be configured to collapse in response to acollapsing force that is substantially equal to the activation force,such that both the collapsible layer collapses and the sensor layereffectuates the key press in response to application of the collapsingforce.

The collapsible layer may have a non-linear force profile. Thenon-linear force profile may follow an S-curve profile. In someembodiments, a spacer stiffness determines the activation force requiredto effectuate the key press. The collapsible layer may includecontinuous fiber knitted into a three-dimensional spacer fabric. Thecontinuous fiber may include fibers of natural or synthetic origin andconsist of mono- or poly-filament.

In some embodiments, the sensor layer includes a sensor membrane. Thesensor membrane may include a first conductive contact layer, a secondconductive contact layer, and a non-conductive spacer layer disposedbetween the first and second contact layers. The spacer layer may have aspacer thickness. The spacer layer may include an opening such that thefirst and second contact layers are separated by empty space within theopening. The first and second contact layers may make contact within theopening in response to the activation force that pushes the first andsecond contact layers together.

The input device may further include a keycap coupled to the collapsiblelayer and directly above the opening of the spacer layer. In certainembodiments, the input device may further include a filler materialdisposed in the openings of the spacer layer to tailor the activationforce required to push the first and second contact layers together. Thefiller material may be a resistive material. In some embodiments, thebottom contact layer and the top contact layer comprise bottom and topconductive combs, respectively. The bottom conductive comb may bearranged substantially perpendicular to the top conductive comb. Inembodiments, the input device may further include a non-conductivecovering. A portion of the non-conductive covering may be disposedbetween the collapsible layer and the sensor layer.

In embodiments, a method of forming an input device includes forming asensor layer configured to effectuate a key press upon application of anactivation force, and forming a collapsible layer coupled to the sensorlayer. The collapsible layer may be configured to collapse in responseto a collapsing force that is substantially equal to the activationforce, such that both the collapsible layer collapses and the sensorlayer effectuates the key press in response to application of thecollapsing force.

The method may further include forming a non-conductive covering. Aportion of the non-conductive covering may be disposed between thecollapsible layer and the sensor layer.

In certain embodiments, a computer system includes a processor and aninput device coupled to the processor. The input device may include asensor layer configured to effectuate a key press upon application of anactivation force, and a collapsible layer coupled to the sensor layer.The collapsible layer may be configured to collapse in response to acollapsing force that is substantially equal to the activation force,such that both the collapsible layer collapses and the sensor layereffectuates the key press in response to application of the collapsingforce.

The collapsible layer may have a non-linear force profile. Thenon-linear force profile may follow an S-curve profile.

A better understanding of the nature and advantages of embodiments ofthe present invention may be gained with reference to the followingdetailed description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a simplified diagram of a computer system, according toembodiments of the present invention.

FIG. 2 is a simplified block diagram of a system configured to operatean input device, according to embodiments of the present invention.

FIGS. 3A-3B are simplified diagrams of a solid state sensor layer,according to embodiments of the present invention.

FIG. 4 is a broad top-view perspective of an inner component for aninput device, according to embodiments of the present invention.

FIG. 5 is a zoomed-in top-view perspective of the inner component forthe input device, according to embodiments of the present invention.

FIG. 6 is a simplified diagram of a cross-sectional view of an inputdevice, according to embodiments of the present invention.

FIG. 7 is a simplified diagram illustrating details of a collapsiblelayer, according to embodiments of the present invention.

FIG. 8A is a simplified diagram illustrating a collapsible layerresisting downward force applied by a user's finger, according toembodiments of the present invention.

FIG. 8B is a simplified diagram illustrating a collapsible layerinteracting with a sensor layer, according to embodiments of the presentinvention.

FIG. 9 is a simplified diagram of a mechanical key.

FIG. 10 is a simplified diagram of a foam key.

FIG. 11 is a line chart illustrating various force profiles of inputdevices, according to embodiments of the present invention.

FIG. 12 is a flow chart illustrating a method of forming an inputdevice, according to embodiments of the present invention.

FIG. 13 is a simplified diagram of a cross-sectional view of an inputdevice with electrical components, according to embodiments of thepresent invention.

FIG. 14 is a simplified diagram of a perspective view of an input devicewith electrical components incorporated in a protective cover, accordingto embodiments of the present invention.

DETAILED DESCRIPTION

Input devices, such as keyboards, having good comfort and feel whileachieving a compact size are disclosed herein. The compact keyboard maybe a solid state keyboard that includes a collapsible layer disposed ontop of a sensor layer. The collapsible layer may be structured to have aforce profile that is substantially similar to an S-curve force profile.The collapsible layer and sensor layer may be designed with one anotherin mind such that when the collapsible layer collapses upon applicationof force from a user, the sensor layer effectuates a key press in aseamless manner. In embodiments, the sensor layer may include a pair ofcontacts that are pressed against one another to effectuate a key press.The collapsible layer and sensor layer may have thin profiles such thatthe overall thickness of the solid state keyboard is compact. Thematerials used to form the solid state keyboard may enable it to beflexible so that it could be easily bent and/or rolled up. Additionally,because the collapsible layer has a unique force profile, the solidstate keyboard is comfortable and has a feel that is comparable tomechanical keys when used.

The solid state keyboard may be used as an input device in a computersystem. To better understand the role of the solid state keyboard, anexemplary computer system is described.

I. Exemplary Computer System

FIG. 1 is a simplified schematic diagram of a computer system 100according to an embodiment of the present invention. Computer system 100includes computer 110, monitor 120, keyboard 130, and mouse 140. Inembodiments, keyboard 130 can be any suitable device capable of beingused to convert analog input signals into digital signals for computerprocessing. As an example, keyboard 130 may be a input device with aplurality of keys that can be pressed to effectuate a key press. The keypress may cause a corresponding input to be generated in computer system100. For computer system 100, keyboard 130 and mouse 140 can beconfigured to control aspects of computer 110 and monitor 120.

In some embodiments, computer 110 may include a machine readable medium(not shown) that is configured to store computer code, such as keyboarddriver software, and the like, where the computer code is executable bya processor (not shown) of the computer 110 to affect control of thecomputer 110 by keyboard 130. The various embodiments described hereingenerally refer to keyboard 130, or similar input device, however itshould be understood that keyboard 130 can be any input/output (I/O)device, user interface device, control device, input unit, or the like.

FIG. 2 is a simplified block diagram of a system 200 configured tooperate keyboard 130, according to certain embodiments of the invention.System 200 includes control circuit 210, memory array 220, powermanagement system 230, and communication system 240. Each of the systemblocks 220, 230, and 240 can be in electrical communication with thecontrol circuit 210. System 200 may further include additional systemsthat are not shown or discussed to prevent obfuscation of the novelfeatures described herein. Each system block 220, 230, and 240 may beindividual electrical components that perform necessary functions forkeyboard operation. System blocks 220, 230, and 240 may be implementedas separate modules, or alternatively, more than one system block may beimplemented in a single module.

In certain embodiments, control circuit 210 comprises one or moremicroprocessors (μCs) and can be configured to control the operation ofsystem 200. Alternatively, control circuit 210 may include one or moremicrocontrollers (MCUs), digital signal processors (DSPs), or the like,with supporting hardware and/or firmware (e.g., memory, programmableI/Os, etc.), as would be appreciated by one of ordinary skill in theart. In embodiments, control circuit 210 may be configured to generatean input signal when a key press is effectuated. Effectuation of the keypress may be performed by connecting two conductive lines with oneanother. When connected, a circuit may be completed and an input signalmay be generated according to the specific key pressed. Details of suchoperation will be discussed further herein.

Memory array 220 may be configured to store information pertaining tokeys of a keyboard. For instance, information stored in memory array 220may establish an input value for a corresponding key of the keyboard sothat when a key is pressed, the corresponding input value may begenerated. Additionally, memory array 220 can store one or more softwareprograms to be executed by processors (e.g., in control circuit 210). Itshould be understood that “software” can refer to sequences ofinstructions that, when executed by processing unit(s) (e.g.,processors, processing devices, etc.), cause system 200 to performcertain operations of software programs. The instructions can be storedas firmware residing in read only memory (ROM) and/or applicationsstored in media storage that can be read into memory for processing byprocessing devices. Software can be implemented as a single program or acollection of separate programs and can be stored in non-volatilestorage and copied in whole or in-part to volatile working memory duringprogram execution.

Power management system 230 can be configured to manage powerdistribution, recharging, power efficiency, and the like, for keyboard130. In some embodiments, power management system 230 can include abattery (not shown), a USB based recharging system for the battery (notshown), and power management devices (e.g., low-dropout voltageregulators—not shown). In certain embodiments, the functions provided bypower management system 230 may be incorporated into the control circuit210. The power source can be a replaceable battery, a rechargeableenergy storage device (e.g., super capacitor, Lithium Polymer Battery,NiMH, NiCd), or a corded power supply. The recharging system can be anadditional cable (specific for the recharging purpose) or it can use themouse's USB connection to recharge the battery. In embodiments,components of power management system 230 are designed to have a lowprofile to maximize portability of the solid state keyboard. Forinstance, the components may have a thickness similar to the thicknessof the solid state keyboard.

Communications system 240 can be configured to provide wirelesscommunication with the computer 110, or other devices and/orperipherals, according to certain embodiment of the invention.Communications system 240 can be configured to provide radio-frequency(RF), Bluetooth, infra-red, or other suitable communication technologyto communicate with other wireless devices. System 200 may optionallycomprise a hardwired connection to computer 110. For example, keyboard130 can be configured to receive a Universal Serial Bus (USB) cable toenable bi-directional electronic communication with computer 110 orother external devices.

Some embodiments may utilize different types of cables or connectionprotocol standards to establish hardwired communication with otherentities.

Although certain necessary systems may not expressly discussed, theyshould be considered as part of system 200, as would be understood byone of ordinary skill in the art. For example, system 200 may include abus system to transfer power and/or data to and from the differentsystems therein.

It should be appreciated that system 200 is illustrative and thatvariations and modifications are possible. System 200 can have othercapabilities not specifically described herein. Further, while system200 is described with reference to particular blocks, it is to beunderstood that these blocks are defined for convenience of descriptionand are not intended to imply a particular physical arrangement ofcomponent parts. Further, the blocks need not correspond to physicallydistinct components. Blocks can be configured to perform variousoperations, e.g., by programming a processor or providing appropriatecontrol circuitry, and various blocks might or might not bereconfigurable depending on how the initial configuration is obtained.

Embodiments of the present invention can be realized in a variety ofapparatuses including electronic devices implemented using anycombination of circuitry and software. Furthermore, aspects and/orportions of system 200 may be combined with or operated by othersub-systems as required by design. For example, customization controlblock 220 may operate within control circuit 210 instead of functioningas a separate entity. In addition, the inventive concepts describedherein can also be applied to a mouse, keypad, or other similar inputdevice. For example, a mouse can include buttons incorporating thesensor layer and collapsible layer as described in configurationsherein. The foregoing embodiments are not intended to be limiting andthose of ordinary skill in the art with the benefit of this disclosurewould appreciate the myriad applications and possibilities.

In embodiments, keyboard 130 may be structured to have a compact size,while achieving good comfort and feel. Such structure is discussed inmore detail further herein.

II. Solid State Input Device

Solid state devices are devices that are built with solid materials inwhich charge carriers are confined. The charge carriers may flow throughconductive lines to transmit signals.

An array of such devices may form a sensor layer, such as a sensormembrane, for an input device. In such circumstances, the input devicemay be considered as a solid state input device. The sensor membrane maygenerate input signals when specific regions are depressed. Unliketraditional input devices that include mechanical structures, e.g.,springs, hinges, and the like, solid state input devices may not includesuch moving parts. Instead, solid state input devices may be primarilyformed of the sensor membrane containing a large number of conductivelines for signal routing. Such solid state input devices may effectuatea key press by connecting two conductive lines by pressing them againstone another, as discussed herein. Although a sensor membrane isdiscussed, one skilled in the art understands that any suitable sensorstructure may be used in the solid state devices discussed hereinwithout departing from the spirit and scope of the present invention.For instance, the sensor layer may include a dome structure foreffectuating a key press.

FIG. 3A illustrates an exemplary sensor membrane 300 for effectuating akey press according to embodiments of the present invention. Sensormembrane 300 may be formed of a top conductive contact layer 302, abottom conductive contact layer 304, and a non-conductive spacer layer306. Spacer layer 306 may have an opening 308 that separates top contactlayer 302 from bottom contact layer 304 such that the two layers areinitially electrically isolated from one another. Spacer layer 306 canbe a printed feature with a sufficient physical dimension or a cutoutlayer from a continuous sheet. Under application of force, top contactlayer 302 and bottom contact layer 304 may connect with one another, asshown in FIG. 3B.

FIG. 3B illustrates sensor membrane 300 when an external downward force310 is applied to effectuate a key press. Force 310 may depress topcontact layer 302 downward into opening 308 such that it connects withbottom contact layer 304. In embodiments, top contact layer 302 bendsdownward upon application of force 310, and may return to its unbentshape upon removal of force 310. When connected, a circuit may becompleted and current may flow between top and bottom contact layers 302and 304. The flow of current may be used to generate in input device toeffectuate a key press. Details of how sensor membrane 300 may beconfigured to alter an amount of force to effectuate a key press will bediscussed further herein.

Although FIGS. 3A-3B may illustrate a sensor membrane 300 having oneopening 308 within which top contact layer 302 may depress to effectuatea key press, embodiments are not so limited. For instance, sensormembrane 300 may be a subset of an entire inner component for a solidstate keyboard device, as shown in FIG. 4.

FIG. 4 illustrates a top-view perspective of an inner component 400 foran exemplary keyboard, such as keyboard 130, according to embodiments ofthe present invention. In some embodiments, inner component 400 may be acomponent designed to enable effectuation of a key press for a solidstate keyboard. Inner component 400 may include a sensor layer 402 and aplurality of key regions 404. Sensor layer 402 may be a structure thatconforms to the general shape of a keyboard and may contain variousconductive routing lines for transmission of signals from key regions404. Sensor layer 402 may include a sensor membrane, such as sensormembrane 300. In embodiments, key regions 404 are areas of sensor layer402 where keys for a keyboard are located. For instance, a key region404 may be an area where the “enter” button for a keyboard will beplaced. Accordingly, key regions 404 may be organized in a standardkeyboard arrangement.

In embodiments, key regions 404 include structures that enable a keypress when force is applied, such as when a user presses a key on akeyboard. For example, key regions 404 are regions where openings arelocated to allow a top contact layer to depress and connect with abottom contact layer when force is applied to effectuate a key press, asdiscussed herein.

FIG. 5 is a close-up view of an area of inner component 400 to bettershow the arrangement of key regions 504. In embodiments, key regions 504may include an arrangement of conductors that effectuate a key presswhen force is applied. For instance, key regions 504 may include atleast two conductors: a first conductor 502 and a second conductor 504.First and second conductors 502 and 504 may correspond with top andbottom contacts 302 and 304, respectively. Each conductor may be aportion of a larger circuit that is designed to effectuate a key presswhen the conductors 502 and 504 connect with one another.

Conductors 502 and 504 may be structured to allow effectuation of a keypress across a maximum area of key regions 504. For instance, conductor502 and 504 may have a comb-like structure that spans across an entirearea of key regions 504. As shown in FIG. 4, the comb-like structure ofconductors 502 and 504 may include an array of elongated fins thatextend across a majority of a length of each key region 504. Further,the elongated fins may each be positioned beside one another such thatthe array of fins spans across each key regions 504. The number ofelongated fin may be sufficient to span across key regions 504. Morenumber of elongated fins may be needed to span across larger distancesof key regions 504.

In embodiments, conductors 502 and 504 are oriented such that they maycontact one another when force is applied. For instance, conductors 502may be perpendicular to conductors 504. That way, a grid-like patternmay be formed across each entire key region 504. In other embodiments,conductors 502 may be parallel, but overlapping with, conductors 504.Although embodiments illustrate the elongated fins as having a verticalconstruction, embodiments are not limited to such configurations. Forinstance, the fins may have a curved, zig-zag, and any otherconstruction to contact one another when force is applied whilemaximizing an area for effectuating a key press.

In embodiments, the space between conductors 502 and 504 may bedetermined based upon an activation force, which may be tuned accordingto a collapsing layer, as will be discussed further herein.

III. Construction

FIG. 6 illustrates a cross-sectional view of an inner component 600 fora solid state keyboard according to embodiments of the presentinvention. It is to be appreciated that FIG. 6 illustrates a subset ofan entire inner component for a solid state keyboard. Inner component600 may include several parts which will be discussed further herein.

A. Sensor Layer

Inner component 600 may include a sensor layer 602, such as sensormembrane 300 discussed in FIG. 3, that can be depressed to effectuate akey press. In embodiments, sensor layer 602 may be formed of a topconductive contact layer 604 and a bottom conductive contact layer 606.The top contact layer 604 and bottom contact layer 606 may be portionsof an open circuit that closes when the contact layers touch oneanother. In some embodiments, top contact layer 604 may correspond withconductor 502 of FIG. 5, and bottom contact layer 606 may correspondwith conductor 504. As will be discussed further herein, top and bottomconductive contact layers 604 and 606 may be formed of a flexible basematerial coated with a conductive material to allow movement ofelectrons. The flexible base material allows the conductive contactlayers 604 and 606 to bend during effectuation of a key press asdiscussed herein.

In embodiments, sensor layer 602 also includes a non-conductive spacerlayer 608. Spacer layer 608 may be disposed between top contact layer604 and bottom contact layer 606. A plurality of openings 610 may bedisposed within spacer layer 608 such that some regions of contactlayers 604 and 606 do not have spacer layer 608 disposed between them.Openings 610 may be located in areas of the spacer layer 608 thatcorrespond to locations of keys for a keyboard, such as key regions 404discussed herein with respect to FIG. 4. Openings 610 may separatecontact layers 602 and 604 from one another by a certain distance. Thedistance may be determined by a height of spacer layer 608.

Openings 610 may be designed to allow effectuation of a key press whendownward force is applied to top contact layer 604 in the area whereopening 610 is located. For instance, openings 610 may electricallyisolate top contact layer 604 from bottom contact layer 606, but alsoenable them to make contact with one another when downward force isapplied upon top contact layer 604. When downward force is applied, topcontact layer 604 may bend within opening 610 and make contact withbottom contact layer 604. When such contact is made, the open circuitmay be closed and a signal may be generated, thereby effectuating a keypress.

In embodiments, a minimal amount of force required to make top contactlayer 604 touch bottom contact layer 606 may be defined as an activationforce. The activation force may be selected to be high enough to allow auser to rest his or her fingers on the keys of a keyboard withoutinadvertently effectuating a key press, but not so high as to make itdifficult to depress when the user intends to effectuate a key press.Thus, in some embodiments, the activation force may range between 60 to100 gram-force (gf), and preferably about 50 gf in certain embodiments.

To achieve this target activation force, sensor layer 602 may bemodified. In embodiments, sensor layer 602 may be modified to achievethe target activation force in various ways. For instance, a thicknessof spacer layer 608 may be modified to be thicker or thinner. Having athicker spacer layer 608 increases the distance between top contactlayer 604 and bottom contact layer 606. Thus, top contact layer 604 mayneed to traverse more distance to touch bottom contact layer 606. Havingto traverse more distance may result in a higher activation force.Alternatively, having a thinner spacer layer 608 decreases the distance,thereby making it easier to effectuate a key press. In otherembodiments, a stiffness of top contact layer 604 may be modified toachieve the target activation force. A stiffer top contact layer 604 mayresult in a higher activation force because it may be more difficult topress down to bend top contact layer 604.

Another way to modify sensor layer 602 to achieve a target activationforce is to include a filler material in openings 610. The fillermaterial may be any non-conductive material that resists deformation oftop contact layer 604. For instance, the filler material may be aviscous solution. The amount by which the activation force increases ordecreases may depend upon the viscosity of the filler material. Moreviscous filler materials may result in higher activation forces whencompared to less viscous filler materials. However, including anyviscous material may result in a higher activation force when comparedto not including any viscous material. When no viscous material is used,openings 610 may be filled with air.

Yet another way to modify sensor layer 602 to achieve a targetactivation force is to alter the thickness of top contact layer 604. Athicker top contact layer 604 will more strongly resist deformation,such as when top contact layer 604 is being bent toward bottom contactlayer 606 during effectuation of a key press. Accordingly, thicker topcontact layers 604 may result in higher activation forces, and viceversa. One skilled in the art understands that any suitable alterationof contact layers 604 and 606, openings 610, and spacer layer 608 may beused without departing from the spirit and scope of the presentinvention.

In embodiments, additional spacer structures (not shown) may be includedin openings 610 to prevent inadvertent contacting between top and bottomcontact layers 604 and 606. Inadvertent contacting may occur becauseexternal forces, such as gravity or compressive forces when sensor layer602 is bent, may cause the two contact layers to contact one another.The amount of force that causes inadvertent contacting may be lower thanthe activation force. In some embodiments, the additional spacers may beformed inside the opening 610 to prevent such inadvertent contactingbetween top and bottom contact layers 604 and 606. For instance, bumps618 formed of a compressible non-conductive material may be formed ontop and/or bottom conductive layers 604 and/or 606. Bumps 614 may bedisposed near the center of opening 610. Additionally, bumps 614 may becompressible to prevent contacting between top and bottom contact layers604 and 606 under low force, but allow contacting under activationforce. In embodiments, bumps 614 prevent contacting under forces below20 gf. In particular embodiments, bumps 614 prevent contacting underforces below 40 gf.

Top and bottom conductive contact layers 604 and 606 spacer layer 608may be formed of any suitable material to enable effectuation of a keypress according to embodiments of the present invention. For instance,all three layers may be formed of a bendable material that may or maynot be covered with materials with specific conductive properties. As anexample, all three layers may be formed of polyethylene terephthalate(PET) films, or better known as polyester films. Because polyester filmsare inherently non-conductive, conductive layers 604 and 606 may becoated with a conductive material to allow effectuation of a key pressas discussed herein. In embodiments, the conductive material may be anysuitable material capable of enabling movement of electrons, such assilver, aluminum, copper, gold, and the like. For instance, top andbottom conductive contact layers 604 and 606 may be formed of apatterned PET base material coated with silver. Spacer layer 608 may notbe coated with a conductive material and may thus remain as anon-conductive material to prevent electrical cross-talk between contactlayers 604 and 606.

Although all three layers may be formed of PET film, embodiments are notso limited. For instance, conductive layers 604 and 606 may be formed ofa thin layer of conductive material, such as a metal. As an example,conductive layers 604 and 606 may be formed of aluminum, copper, gold,and the like, and any combination of such materials in an alloy ordisposed one on top of the other.

Utilizing sensor layer 602 in an input device is advantageous given itslow profile and low cost. However, because of its lack of mechanicalparts, sensor layer 602 may not provide good comfort and feel whenimplemented in a solid state keyboard design by itself According toembodiments of the present invention, sensor layer 602 may be combinedwith a collapsible layer. The combination of sensor layer andcollapsible layer may provide the benefits of compact size and low costwhile achieving good comfort and feel.

B. Covering

In embodiments, sensor layer 602 may be encapsulated by a non-conductivecovering 612. Covering 612 may encapsulate sensor layer 602 to protectsensor layer 602 from intrusion of particles such as dust and debris. Insuch embodiments, covering 612 may cover the entire sensor layer 602. Inalternative embodiments, covering 612 may not cover the entire sensorlayer 602. For example, covering 612 may cover a portion of sensor layer602. Covering 612 may be formed of a material that is non-permeable andflexible. For instance, covering 612 may be formed of a plastic film,rubber, and/or non-permeable fabrics (Tyvek, etc.).

C. Collapsible Layer

Inner compartment 600 may also include a collapsible layer 614 disposedon covering 612 and above sensor layer 602. Thus, a portion of covering612 may be disposed between collapsible layer 614 and sensor layer 602.Keycaps 616 may be attached to a top surface of covering 612 to providea structure upon which a user may apply a downward force to effectuate akey press. In embodiments, keycaps 616 are disposed above openings 610so that when a downward force is applied upon keycap 616, a respectiveopening is depressed to allow top and bottom contact layers 604 and 606to touch one another, as discussed herein.

In some embodiments, keycaps 616 may include keyguides to assist inguiding a user's fingers to certain keycaps. The keyguides may be anysuitable structure and/or contour of keycaps 616 that achieves suchpurposes. For instance, keyguides may be a protrusion on keycaps 616, oran indentation in keycaps 616. In certain embodiments, keycaps 616 mayform a scoop profile such that a user's finger may rest at the bottom ofthe scoop profile. Keycaps 616 may be formed of any suitable materialsuitable for allowing a downward force to effectuate a key press. As anexample, keycaps 616 may be formed of rubber, plastic, metal, and thelike.

According to embodiments of the present invention, collapsible layer 614is a layer that transfers downward force applied to keycap 616 ontorespective key regions of sensor layer 602. Transferring of force ismade when collapsible layer 614 collapses and ceases to sufficientlyresist the applied downward force. Collapsible layer 614 may thus affectthe way keycaps 616 feel when depressed to effectuate a key press. Inembodiments, collapsible layer 614 is constructed to have a non-linearforce profile. Collapsible layer 614 may be designed to create anon-linear profile similar to that of an S-curve profile, as discussedherein, as will be discussed further herein. To achieve the non-linearprofile, collapsible layer 614 may be formed to have a unique structure.For instance, collapsible layer 614 may be formed of a structurecontaining straight, vertical columns that buckle upon application of acertain amount of force, as shown in FIG. 7.

FIG. 7 illustrates a close-up view of a subset of FIG. 6 to betterillustrate the details of collapsible layer 614. Specifically, FIG. 7shows a collapsible key 700 according to embodiments of the presentinvention. As shown, collapsible layer 614 may include a plurality ofcolumns 702. Columns 702 may be an arrangement of vertically-orientedcollapsible structures that resist downward force/pressure appliedagainst top surface 615 of collapsible layer 614. Columns 702 may beevenly spaced apart such that pressure applied against any region of topsurface 615 of collapsible layer 614 may be resisted by the same numberand arrangement of columns 702. In embodiments, columns 702 are formedof continuous fiber that may be knitted into three-dimensional spacerfabric. The fibers can be of natural or synthetic origin and consist ofa mono- or poly-filament. Columns 702 may resist vertical pressure whenits vertical structure is intact. However, when columns 702 buckle,i.e., bend, when a certain amount of downward pressure is applied,columns 702 may cease to provide resistance in the vertical direction.Details of how collapsible layer 614 operates and interacts with sensorlayer 602 is discussed in further detail herein.

D. Interaction of Collapsible Layer and Sensor Layer

FIGS. 8A-8B illustrate how collapsible layer 614 and sensor layer 602interact when downward force/pressure is applied by an external actor,according to embodiments of the present invention. In FIG. 8A, downwardforce 804 applied by a user's finger 802 begins to be applied againstkeycap 616. Since keycap 616 may be formed of a hard material, downwardforce 804 applied to keycap 616 may be transferred against top surface615 of collapsible layer 614. Columns 702 disposed under keycap 616 mayresist downward force 804. In embodiments, columns 702 may resist acertain amount of force before giving away, e.g., buckling. Forinstance, columns 702 may resist a threshold amount of downward forceuntil columns 702 buckle. As shown in FIG. 8A, as columns 702 resistdownward force 804, columns 702 may slightly bend, but not buckle.“Buckling” as used herein may be defined as a structural collapse ofcolumns 702 such that columns 702 fail to resist any downward force.

As downward force 804 increases to an amount at or above the thresholdamount of downward force, columns 702 may buckle and collapse, as shownin FIG. 8B. During collapse, columns 702 of collapsible layer 614 mayfail to resist downward force 804 and thus allow finger 802 to movedownward. In embodiments, force 804 applied by finger 802 simultaneouslyapplies pressure against sensor layer 602. Thus, when sufficientpressure is applied by finger 802 and collapsible layer 614 collapses, akey press may be effectuated. In embodiments, effectuation of the keypress may occur when downward force 804 presses down upon top conductivecontact layer 604 of sensor layer 602, causing top contact layer 604 tobend. Downward force 804 may cause top contact layer 604 to bend to apoint where it connects with bottom contact layer 606. Once connected,top and bottom contact layers 604 and 606 may close a circuit and allowcurrent to flow to generate an input signal, thereby effectuating a keypress.

In embodiments, the amount of force resisted by collapsible layer 614may be plotted against a travel distance of keycap 616. The resultingcurve may establish a force profile curve of collapsible layer 614. Theforce profile curve of collapsible layer 614 may be labeled as“collapsible key curve.” The collapsible key curve may have a profilesimilar to an S-curve profile of a mechanical key, but different than acurve profile of a foam key, as will be discussed further herein.

E. Mechanical and Foam Keys

To better understand how the keys are different from one another, amechanical and foam key is illustrated in FIGS. 9-10 and brieflydescribed herein. FIG. 9 illustrates a mechanical key 900, such as ascissor key. Mechanical key 900 may include a keycap 902 and aprotrusion 904 disposed below keycap 902. Protrusion 904 may extend froma bottom surface of keycap 902. Actuator arms 908 and 906 may crisscrossone another like blades of a scissor.

Additionally, actuator arms 908 and 906 may be attached to one anotherat hinge 910. Hinge 910 may allow the actuator arms 908 and 906 torotate respective to one another. A dome 912 may be disposed on acircuit board 914. Dome 912 may be positioned such that protrusion 904may compress dome 912 when depressed. For instance, dome 912 may bedisposed below the protrusion 904. To effectuate a key press, a downwardforce is applied against keycap 902 which causes actuator arms 908 topivot against one another at hinge 910. As the keycap 902 movesdownward, protrusion 904 may press upon dome 912 to effectuate a keypress. The actuator arms may be configured to provide an S-curveprofile, which will be discussed further herein. Although FIG. 9illustrates an exemplary scissor key, other mechanical keys may be usedto illustrate keys having S-curves. For instance, instead of actuatorarms 908 and 906, one or more springs may be used instead.

FIG. 10 illustrates a foam key 1000. Foam key 1000 includes a keycap1002 disposed on a foam layer 1004. Foam layer 1004 may be formed of aporous material that has a substantially exponential force profile. Inother words, foam layer 1004 resists downward force at an exponentialforce. Foam layer 1004 may provide exponential resistance across theentire layer such that force applied against an edge of keycap 1002 maybe subject to the same amount of resistance from foam layer 1004 as whenforce is applied against a center of keycap 1002. The details of such aforce profile is discussed further herein with respect to FIG. 12. Foamlayer 1104 may be disposed on a sensor layer 1006, such as sensor layer602 discussed herein. Sensor layer 1006 may allow foam key 1000 toeffectuate a key press when depressed.

In embodiments, the force profile of a collapsible key, such ascollapsible key 700, is similar to the force profile of mechanical key900. In contrast, the force profile of collapsible key 700 is notsimilar to the force profile of foam key 1000. A comparison of theseforce profiles are discussed further herein.

F. Force Profile of the Various Keys

FIG. 11 is a graphical chart illustrating three different force profilecurves: a mechanical key curve 1102, a foam key curve 1104, and acollapsible layer key curve 1106. The three curves are plotted onto asingle force profile chart for ease of reference and comparison. Theforce profile chart has an X axis representing distance traveled thatincreases from left to right, and a Y axis representing amount of forceresisting against depression of a key that increases from bottom to top.Although FIG. 11 illustrates axis Y as increasing from 0 to 60 gf andthe X axis as increasing from 0 to 4 mm, other embodiments can havedifferent ranges of values.

Mechanical key curve 1102 may represent a force profile for a mechanicalkey, e.g., mechanical key 900 of FIG. 9, that is substantially similarto an ideal S-curve profile that has great comfort and feel. As shown,mechanical key curve 1102 has an initial steep slope that rapidlyapproaches a threshold force 1108. Threshold force 1108 may represent anamount of force at which the mechanical key depresses. The initial steepslope indicates that the mechanical key strongly resists key travelbecause a little distance is traveled as greater force is applied. Oncethe amount of force reaches threshold force 1108, the mechanical key maydepress, i.e., decrease the amount of force resisting the key press, asindicated by the decreasing slope of mechanical key curve 1102. This mayresult in a feeling as though the key is actually collapsing andeffectuating a key press. Thereafter, the mechanical key curve 1102 maybegin to resist downward application of force and thus curve backupward. This may be because the key is near the end of its travelinglimit 1110, which is a point at which the key is completely depressedand cannot travel any further. When the traveling limit 1110 is reached,the key cannot travel anymore and the curve stops traveling to theright. The dual-changing, i.e., increasing-decreasing-increasing trend,is indicative of the S-curve profile that indicates when a key has goodcomfort and feel when used.

Foam key curve 1104 may represent a force profile for a foam key, e.g.,foam key 1000 of FIG. 10, that has subpar comfort and feel. Foam keycurve 1104 may be a force profile for keys that have a compliant foamlayer, which is utilized by some conventional compact keyboards. Asshown, foam key curve drastically travels a great distance uponapplication of relatively low force. Thus, the foam key does notsufficiently resist applied downward force, indicating that the foam keyis easily depressed and may feel weak. The foam key may begin tosufficiently resists applied downward force when the key travels to apoint near its traveling limit 1110, as shown by the change to a moresteeply sloped curve.

Collapsible key curve 1106 may represent a force profile for acollapsible key, e.g., collapsible key 700 of FIG. 7, utilizing acollapsible layer, such as collapsible layer 614 of FIG. 6, according toembodiments of the present invention. In contrast to foam key curve1104, but in comparison with mechanical key curve 1102, collapsible keycurve 1106 may have a dual-changing force profile. As shown, collapsiblekey curve 1106 may steeply increase to threshold force 1108 when thecollapsible layer is resisting downward force (see FIG. 8A). Thereafter,collapsible key curve 1106 may decrease after reaching threshold force1108 when the collapsible layer buckles (see FIG. 8B). Collapsible keycurve 1106 may then increase until its traveling limit 1110 is reachedwhen the collapsible layer cannot collapse any further (see FIG. 8B).Such increasing, decreasing, and increasing force profile of collapsiblekey curve 1106 gives the collapsible key curve 1106 good comfort andfeel during use. Therefore the thin profile of collapsible layer 614minimizes keyboard thickness while achieving good comfort and feelduring use.

According to embodiments of the present invention, sensor layer 602 andcollapsible layer 614 are designed with one another in mind such thatthe activation force of sensor layer 602 is in tune with the forceprofile of collapsible layer 614. For instance, in embodiments, theactivation force of sensor layer 602 may be substantially similar, ifnot equal to, threshold force 1108 of collapsible key curve 614. Thatway, when a user depresses a key on collapsible layer 614, once the keydepresses after being subject to threshold force 1108, sensor layer 602may simultaneously effectuate a key press. Tuning the activation forceto the force profile of a key utilizing collapsible layer 614 provides acohesive feel when the key is pressed, thereby preserving the goodcomfort and feel of the compressible key.

In embodiments, sensor layer 602 may effectuate a key presssimultaneously with the collapse of collapsible layer 614. As shown inFIG. 11, vertical line 1114 may represent the location of sensor layer602. At the end of the collapse of collapsible layer 614, force may beapplied to sensor layer 602 as collapsible layer 614 presses upon sensorlayer 602. In embodiments, the downward force pressing upon collapsiblelayer 614 may be equal to, if not greater, than the activation force asthe activation force is equal to threshold force 1108. Accordingly, thedownward force may apply activation force against sensor layer 602 andeffectuate a key press. The simultaneous effectuate of a key press andcollapse of collapsible layer 614 gives the user a sense of one cohesivekey press event, instead of two disjointed events.

IV. Method of Forming an Input Device

FIG. 12 is a flow chart illustrating a method of forming an inputdevice, such as a solid state keyboard having collapsible keys,according to embodiments of the present invention. At block 1202, asensor layer, such as sensor layer 602 of FIG. 6, may be formed. Inembodiments, the sensor layer is a sensor membrane that includes a firstconductive contact layer, a second conductive contact layer, and anon-conductive spacer layer disposed between the first and secondcontact layers.

In certain embodiments, the spacer layer may be formed on top of thefirst contact layer. The spacer layer may have a spacer thickness andmay include an opening such that the first and second contact layer areseparated by empty space. The opening may be formed in the spacer layerfollowing formation of the spacer layer. The second contact layer may beformed on top of the spacer layer. In embodiments, the second layer maybe formed such that the first and second contact layers connect withinthe opening in response to an activation force that pushes the first andsecond contact layers together.

At block 1204, a covering, such as covering 612 of FIG. 6, may be formedaround the sensor layer. In embodiments, the covering may encapsulatethe sensor layer such that the covering covers the entire sensor layer.In other embodiments, the covering may cover a portion of the sensorlayer. Thereafter, at block 1206, a non-conductive collapsible layer,such as collapsible layer 614 of FIG. 6, may be formed. The collapsiblelayer may be configured to collapse in response to a collapsing forcethat is substantially equal to the activation force such that both thecollapsible layer collapses and the first and second conductive layersconnect with one another in response to the activation force.

In some embodiments, keycaps may then be formed on the non-conductivecollapsible layer at block 1208. The keycaps may be attached ontonon-conductive collapsible layer by any suitable method. For instance,keycaps may be adhered onto the non-conductive collapsible layer with anadhesive such as epoxy. The keycaps may also be formed of polyurethanehardened on fabric. Other techniques may be used to attach keycaps tothe collapsible layer. For instance, keycaps may be mechanicallyfastened to the collapsible layer. In some embodiments, keycaps may beclipped or screwed onto the collapsible layer.

V. Electrical Component Integration

Using the thin layers results in a solid state keyboard that has anoverall thickness that is substantially thinner than typical mechanicalkeyboards. To maintain such low thicknesses, electrical components 1302,such as control circuit component 210, memory array 220, powermanagement component 230, and communication system component 240discussed herein with respect to FIG. 2, may need to be integrated intoinner component 400 in a particular way to maintain the low thickness.

FIG. 13 illustrates an exemplary arrangement for the electricalcomponents. As shown, electrical components 1302 may be disposed incovering 612 such that covering 612 may protect electrical components1302 from dust and debris. In embodiments, electrical components 1302may include any of the components discussed herein with respect to FIG.2. For instance, electrical components 1302 may include a battery 1306.Battery 1306 may be a part of a power management components, such aspower management component 230 discussed in FIG. 2. Additionally,electrical components 1302 may include a printed circuit board (PCB)1308. PCB 1308 may be part of a control circuit, such as control circuitcomponent 210 discussed in FIG. 2. PCB 1308 may include processorsand/or microcontrollers that are configured to generate input signalsaccording to which key is pressed. The input signals may be any signalsthat correspond to respective keys of a keyboard, such as alphanumericsignals, etc. Collapsible layer 614 may include an extension 1304 thatlaterally extends to cover electrical components 1302. In embodiments,extension 1304 may protect electrical components 1302 from physicalstress that may damage electrical components 1302.

Although electrical components 1302 may be disposed in covering 612,embodiments are not so limited. For instance, electrical components (notshown) may be disposed in a rear protection 1408 for a tablet computeras shown in FIG. 14. The rear protection 1408 may be formed of a solidshell to absorb physical stresses, such as the physical stressesassociated with dropping the tablet on the floor. By incorporating theelectrical components into rear protection 1408, the size of keyboard1402, such as a solid state keyboard according to embodiments herein,may not be affected by the size of the electrical components. Thus,keyboard 1402 may maintain its low profile. In such embodiments, aconnector/hinge 1404 may be implemented to couple keyboard 1402 withrear protection 1408.

Maintaining the low profile of keyboard 1402 maximizes portability.Conventional portable keyboards utilizing solid state technology sufferfrom poor comfort and feel. However, embodiments discussed hereinutilize a collapsible layer having vertical columns to create an S-curveprofile. The collapsible layer may be tuned with the sensor layer toeffectuate a key press seamlessly with the collapse of the collapsiblelayer.

The above description illustrates various embodiments of the presentinvention along with examples of how aspects of the present inventionmay be implemented. The above examples and embodiments should not bedeemed to be the only embodiments, and are presented to illustrate theflexibility and advantages of the present invention as defined by thefollowing claims. For example, although certain embodiments have beendescribed with respect to particular process flows and steps, it shouldbe apparent to those skilled in the art that the scope of the presentinvention is not strictly limited to the described flows and steps.Steps described as sequential may be executed in parallel, order ofsteps may be varied, and steps may be modified, combined, added, oromitted. As another example, although certain embodiments have beendescribed using a particular combination of hardware and software, itshould be recognized that other combinations of hardware and softwareare possible, and that specific operations described as beingimplemented in software can also be implemented in hardware and viceversa.

The specification and drawings are, accordingly, to be regarded in anillustrative rather than restrictive sense. Other arrangements,embodiments, implementations and equivalents will be evident to thoseskilled in the art and may be employed without departing from the spiritand scope of the invention as set forth in the following claims.

1. An input device, comprising: a sensor layer to effectuate a key pressupon application of an activation force; and a collapsible layer coupledto the sensor layer, the collapsible layer to collapse in response toreceiving a collapsing force that is substantially equal to theactivation force, such that both the collapsible layer collapses and thesensor layer effectuates the key press in response to the application ofthe collapsing force, wherein the collapsible layer includes a pluralityof vertical columns comprised of continuous fibers knitted into athree-dimensional spacer fabric, wherein the vertical columns resistcollapse under application of force less than the collapsing force andthat collapse upon themselves under application of force equal to orgreater than the collapsing force, and wherein the applied force isgreater than zero.
 2. The input device of claim 1 wherein thecollapsible layer has a non-linear force profile.
 3. The input device ofclaim 2 wherein the non-linear force profile follows an S-curve profile.4. The input device of claim 1 wherein a spacer stiffness determines theactivation force required to effectuate the key press.
 5. (canceled) 6.The input device of claim 5 wherein the continuous fiber comprisesfibers of natural or synthetic origin and consist of a mono- orpoly-filament.
 7. The input device of claim 1 wherein the sensor layercomprises a sensor membrane, the sensor membrane comprising: a firstconductive contact layer; a second conductive contact layer; and anon-conductive spacer layer disposed between the first and secondconductive contact layers, wherein the spacer layer has a spacerthickness, wherein the spacer layer includes an opening such that thefirst and second contact layers are separated by empty space within theopening, and wherein the first and second conductive contact layers makecontact within the opening in response to an activation force thatpushes the first and second conductive contact layers together.
 8. Theinput device of claim 7 further comprising a keycap coupled to thecollapsible layer and directly above the opening of the spacer layer. 9.The input device of claim 7 further comprising a filler materialdisposed in the openings of the spacer layer to tailor the activationforce required to push the first and second conductive contact layerstogether.
 10. The input device of claim 9 wherein the filler material isa resistive material.
 11. The input device of claim 7 wherein the firstconductive contact layer and the second conductive contact layercomprise bottom and top conductive combs, respectively.
 12. The inputdevice of claim 11 wherein the bottom conductive comb is arrangedsubstantially perpendicular to the top conductive comb.
 13. The inputdevice of claim 1 further comprising a non-conductive covering, whereina portion of the non-conductive covering is disposed between thecollapsible layer and the sensor layer.
 14. A method of forming an inputdevice comprising: forming a sensor layer configured to effectuate a keypress upon application of an activation force; and forming a collapsiblelayer coupled to the sensor layer, the collapsible layer configured tocollapse in response to a collapsing force that is substantially equalto the activation force, such that both the collapsible layer collapsesand the sensor layer effectuates the key press in response toapplication of the collapsing force, wherein the collapsible layerincludes a plurality of vertical columns comprised of continuous fibersknitted into a three-dimensional spacer fabric, wherein the verticalcolumns resist collapse under application of force less than thecollapsing force and that collapse upon themselves under application offorce equal to or greater than the collapsing force, and wherein theapplied force is greater than zero.
 15. The method of claim 14 furthercomprising forming a non-conductive covering, wherein a portion of thenon-conductive covering is disposed between the collapsible layer andthe sensor layer.
 16. A system comprising: a processor; and an inputdevice coupled to the processor, the input device comprising: a sensorlayer to effectuate a key press upon application of an activation force;and a collapsible layer coupled to the sensor layer, the collapsiblelayer to collapse in response to a collapsing force that issubstantially equal to the activation force, such that both thecollapsible layer collapses and the sensor layer effectuates the keypress in response to the application of the collapsing force, whereinthe collapsible layer includes a plurality of vertical columns comprisedof continuous fibers knitted into a three-dimensional spacer fabric,wherein the vertical columns resist collapse under application of forceless than the collapsing force and that collapse upon themselves underapplication of force equal to or greater than the collapsing force, andwherein the applied force is greater than zero.
 17. The computer systemof claim 16 wherein the collapsible layer has a non-linear forceprofile.
 18. The computer system of claim 17 wherein the non-linearforce profile follows an S-curve profile.
 19. The computer system ofclaim 16 wherein a spacer stiffness determines the activation forcerequired to effectuate the key press.
 20. (canceled)